Seed distribution method and apparatus

ABSTRACT

A seeding apparatus comprising: (a seed distribution metering means including a rotating d drum with apertures on its periphery and a vacuum generator for generating a suction pressure inside the drum so that seeds are attracted to the apertures; (b) feeding system including a hopper, gravitational acceleration chamber, velocity controlling elements such as a flap and continuous belts for feeding seeds at a required amount and speed to the drum; (c) release mechanisms including an air-jet for releasing metered seeds from the drum along a selected trajectory while unselected seeds follow another trajectory, delivery device including an adjustable flow venturi and electronic sensor for controlling delivery of metered seeds.

FIELD OF THE INVENTION

This invention relates to a method of seed distribution and an apparatusfor achieving this. However the invention is also related todistribution of other particulate matter in the field of farmingincluding fertilisers, fungicides, insecticides, herbicides andmixtures. Throughout this document reference to the word “seeds”includes singular seed and plural seeds and also includes otherparticulate matter in the field of farming including particulate formsof fertilisers, fungicides, insecticides, herbicides and mixtures.

BACKGROUND ART

For many plant species there has been determined a relationship betweenplant populations or densities on a given area and the resulting yields.Overcrowding reduces yield due to excessive competition between plantsfor light, moisture and nutrients as well as increasing risk of diseasedue to inadequate ventilation. Underpopulating reduces yield due tounused or wasted potential cropping area. This relationship applies tomost crops. However in this document an illustrative reference will bemade to one type of cereal crop-wheat. This is by way of example and isnot limiting.

The sowing operation is very important in determining the yield of aparticular crop. Most seeding apparatuses used in broad acre wheatcropping use a “sprinkle” technique to generally toss seeds in rowsabout 150 millimeters or more apart. These seeds are initially meteredout using rollers or various shaped gears adjusted to give selected flowrates. Pneumatic systems can be used to carry the seeds through a systemof pipes to divider heads which separate the seeds into multipleelongated channels that can extend laterally away from the seeder over anumber of rows where it is allowed to sprinkle into the row.

Usually the seeding rate is determined by the seed flow rate from theapparatus however this is an average flow rate. It can be seen thatalthough in this sprinkling there might have been some initial meteringthis becomes only an average metering at the various outlets. Furtherthe drop from a channel outlet can result in its own variation ofplacement.

This result might seem to fulfill the required distribution to produce amaximum yield on the macro level but due to the affect of overpopulationand underpopulation on the micro level the average macro distribution ofseed does not result in maximum yield. The overall result is that therecan be 50% or more of the seeds in an overpopulated or underpopulatedarrangement on the micro level although the average might be near therequired. Each patch of overpopulated or underpopulated seeds is a microgrowing location with its deficits because of the immediate vicinity andis not particularly compensated by the average macro location populationdensity.

Less competition from neighbours for root space, nutrients, moisture andlight all contribute to an increase in yield made possible throughvigorous early growth of seedlings in the crop establishment phase. Thisresults in earlier ground cover with the shading by crop leaves slowingsoil moisture loss from sun and wind as well as smothering weeddevelopment. All these factors are known to dramatically assist yields.However on the micro level if there is overpopulation there is overcompetition resulting in a decrease of yield. Further there is increasedrisk of disease from insufficient ventilation. Alternatively if thespacing is considerable there is space for weeds to establish or openareas which are unproductive and which increase the likelihood of dryingout the soil. Therefore it is the balance and correct spacing on themicro level which is required for maximum yields. To this end theoverall percentage of overpopulated and underpopulated sowing must besubstantially reduced.

There are a range of known sowing apparatuses in use at present. Some ofthese use vacuum systems to pick up seeds and to break the vacuum torelease the seed for planting. Disc and drum vacuum planters are twotypes of vacuum systems.

A disc system is shown in U.S. Pat. No 4,469,244 which discloses asuction-type distributor for a single-seed seeder with a rotaryapertured disk. The distributor includes an aperture disk rotating in acasing and two adjoining selector plates pivoted from the casing andprovided with alternate projections spaced on their edges extendingaround the path of apertures on the disk so as to straddle said path.The relative angular position of the two plates are adjustable by meansof a single lever provided with cams and pivoted on casing.

A drum system is shown in U.S. Pat. No. 4,306,509 which discloses anapparatus for continuously metering seeds onto a seedbed andsimultaneously pressing the seeds into the soil. The seed plantingapparatus includes a drum adapted to be moved in rolling contact acrossthe seedbed, and which transports seeds on its peripheral wall from ahopper to the seedbed. The seeds are retained against apertures in theperipheral wall by means of a vacuum transmitted to the aperturesthrough manifolds within the drum that are interconnected with a vacuumpump by means of individual hoses. A cam interrupts the vacuum bycompressing the hoses when the seed-bearing apertures contact theseedbed, thereby releasing the seeds and pressing them into the soil.The seeds are preferably placed on the seedbed in a uniformly spacedarray predetermined by the uniform alignment and spacing of theapertures on the wall of the drum. An air brush is also included toremove substantially all excess seeds from the apertures before theapertures rotate from beneath the hopper, and a brush removes soil anddebris from the exterior wall of the drum before the apertures re-enterthe hopper.

Another system is shown in U.S. Pat. No. 6,564,729 which has a vacuumseed metering assembly for evenly distributing seeds from a seed hopperincludes a rotating perforated drum and a pair of stationary wallsforming a suction area and a release area inside the drum. The suctionarea is adjacent a seed hopper such that individual seeds are held toapertures in the drum by suction as the apertures pass by the seedhopper. As the drum rotates, each seed is released into an associateddistribution tube when the aperture passes into the release area.

A major problem with such systems is they operate at relatively slowspeeds, which thereby restricts the machines planting speed. All knownvacuum planter apparatuses using rotating drums or discs pick upindividual stationary seeds from a pick-up area and rotate the seeds toa spaced drop off location. This can only be achieved at relatively lowrotation speeds. At higher speeds the moving drum or disc surface passesthe stationary seeds in the pickup zone too quickly to pick up the seed.Therefore the majority of these vacuum planter machines are limited tomaximum sowing ground speeds of about 12 to 15 kilometers per hour.

It is therefore a first object of the invention to improve maximum yieldby providing a seed distribution method and apparatus which improves themicro growing location by lowering the percentage of overpopulated orunderpopulated seed density.

It is a second object of the invention to provide a method of seeddistribution and a seeding apparatus, which allows accurate fasterseeding than the above conventional means.

It is a third object of the invention to provide a method for theplacement of the individual seeds within each row at a selected spacingtogether with the ability to space multiple rows each at a selecteddistance apart, both these being variable and easily changed, to providenumerous sowing grid options.

It is a fourth object of the invention to provide an apparatus which canplace predominantly individual seeds at considerable speed enabling therapid sowing of a grid pattern which gives the optimum plant populationoutcome required for a particular crop.

It is a further object of the invention to provide an improved method ofseed distribution and a seeding apparatus, which overcomes or at leastameliorates the problems of the prior art.

SUMMARY OF THE INVENTION

In accordance with the invention there is provided a method of seeddistribution and a seeding apparatus for achieving this, which includesa seed feed system and a moving metering system with the feed systemproviding an acceleration of seed that provides substantially stationaryrelative velocity of seed from the seed feed system to the movingsurface of the metering system. Such substantially relative velocityincludes velocity of the seeds and the moving surface of metering systemof the seeding apparatus being relatively slightly slower or slightlyfaster than each other.

The invention also provides a seeding apparatus for providing singleseed placement from a continuously moving apparatus in a predetermined,uniformly spaced array, and the seeding apparatus including a frameintegral with or attachable to a vehicle; a drum means mounted on theframe and having a cylindrical peripheral wall with a predeterminedarrangement of a plurality of apertures; drum rotation means forrotatably mounting said drum means on said frame with the axis of saiddrum means extending substantially horizontally; a vacuum generatingmeans connected with said drum means and operatively communicating withsaid apertures to provide a vacuum suction through the apertures;receival hopper means mounted on the frame for receiving seed andcommunicating with a feeding system mounted alongside the drum andhaving an acceleration means for feeding seed from the receival hopperto the external surface of the drum means at a speed; and a releasemechanism for countering the hold of the vacuum suction on the seeds;whereby as the drum rotates the seeds from the hopper means are heldagainst the apertures by the reduced pressure and are carried on theperipheral wall of said drum means from said hopper means to the releasemechanism whereat the seeds are released into the seedbed. The seeds canbe released at the release mechanism and fall straight down to theseedbed by gravitational means but they would usually be conveyed fromthe release mechanism along delivery tubes the ends of which are set tothe row spacings required and from which the seeds are released into theseedbed.

The acceleration means for feeding seed from the receival hopper to theexternal surface of the drum means can be at a speed in a range fromless than, to substantially equal to, to greater than the speed ofrotation of the surface of the drum means. The upper speed limitingfactor is that providing seeds at speed substantially greater than speedof the drum will knock off the attached seeds. The lower speed limitingfactor is the effectiveness of the rotary pick up to be able to provideseed to allow fast sowing without limiting the ground speed of thesowing apparatus but preferably the differential should not be greaterthan 20%. Preferably the speed is substantially the same as the surfacespeed of the drum.

The acceleration means of the feeding system can be gravitational,mechanical, pneumatic or combinations of any of the above.

An example of a gravitational system is a gravity accelerator includinga flow control valve at the top of a substantially vertical accelerationchamber with a flow restriction means providing seed density and speedcontrol at the bottom of the chamber thereby presenting seeds asrequired at the moving drum surface.

An example of a mechanical device can be one or more belts frictionallyengaging the seed with the belt speed controlled relative to the drumsurface speed.

An example of a combination would be the seeds are first accelerated bygravity and then these moving seeds are presented to the moving belt/swhich control the speed of the seeds by accelerating them or acting as abraking system to give the required presentation speed at the point ofcontact with the drum surface. In one form there are one or more beltsfrictionally engaging the seed with the belt speed controlled relativeto the drum surface speed.

In other mechanical forms the belts can be replaced by speed controlleddriven rollers or a velocity controlled flap that alters aperture togive the required presentation speed.

In another form the acceleration means can be an air jet for blowingseed out along a close circumferential or tangential path at a speedsubstantially equal to the drum means rotation speed.

The feeding system can be mounted on the same diametrical side as therelease mechanism or aligned at a circumferential spacing.

The release mechanism can be a mechanical or pneumatic (air jet)deflection system. In one form the deflection system is a frictionalbrush system externally of the drum means or can be a vacuum cut-offmeans operating internally of the drum means such as a roller. The drumcan have on its surface or be constructed of material which enhances itsability to accelerate and capture seeds thereon.

The release mechanism can provide a release before at or beyond thevertical tangent of the drum means to ensure a diversion of the releasedseed away from a vertical fall to form a metered seed releasetrajectory. The point of release can be anywhere after the trajectory ofthe unmetered seed is established. The object of the release mechanismis to form a second distinct separate trajectory for the selectedmetered seeds. It is therefore possible using a smaller diameter drumrotating clockwise to establish an unselected seed trajectoryoriginating from the 2 o'clock tangent. This then can provide a releasepoint before the vertical tangent. The material which is not metered byvacuum contact with the drum means forms the unselected particletrajectory. This trajectory can lead to a recycle means in which theunselected particles are returned to an input of the system such as thereceival hopper.

The metered seed sent on the metered seed release trajectory can befurther controlled by an adjustable venturi system to control an exitspeed of seeds. The venturi does not control the number of seeds but canvary the flow speed of the seed inside the delivery tubes. The exitspeed can be controlled such that the exit speed is substantiallyopposing the speed of the vehicle on which the seeding apparatus isloaded to provide a relatively stationary deposit of the seeds.

The present invention can use a rotating perforated drum containing aninternal partial vacuum or area of considerably lower pressure than theatmospheric pressure on the outside to attach seeds onto the apertureson its outer surface at high rotational speeds. This is achieved byaccelerating the seeds and presenting them at a particular section ofthe drum travelling at or near the same speed and travel direction asthe apertures on the outside surface of the drum, resulting inconsiderably increased sowing machine ground speeds.

The invention also provides a method for introducing the seeds into thesoil at speeds (previously unattainable by ground contacting seedingmachines) as well as the controlled venturi release of seeds.

It can be seen that the invention overcomes the restrictions of theprior art by applying the principle that when two or more objects aretravelling next to each other in the same direction and at the samespeed they will appear stationary relative to each other irrespective oftheir speed relative to a separate stationary object. Therefore itfollows that accelerating the seeds so that at a given point in therotation of the drum surface they travel in close proximity to and insubstantially the same direction and speed as the apertures on a drumsurface the seeds will be picked up as if both seed and aperture arestationary relative to each other. As absolute vacuum is the maximumtheoretical adhesion pressure available a situation will eventually bereached where the force from the rotation of the drum will be greaterthan the force holding the seed onto the surface. However using theinventive method described rotational speeds far greater than those usedon present seeding machines will be attained.

The resulting invention allows placement of individual seeds within eachrow at a selected spacing together with the ability to space multiplerows each at a selected distance apart, both these being variable andeasily changed. The inter-relationship between the aperture spacingwithin a row on a drum surface, and the spacings between the rowsdetermined by the positioning of the delivery tube exits, and therotating drum surface speed, and the ratio of the ground forward speedto the drum surface speed—all these factors being variable—providesnumerous sowing grid options. The size of the aperture also beingvariable between interchangeable drums allows for a numerous number ofseed varieties to be sown with this apparatus.

Also the invention provides an apparatus which can place predominantlyindividual seeds at considerable speed. This apparatus would bebeneficial in the pursuit of increased yields by enabling the selectionof a sowing grid pattern which gives the plant population outcomerequired for a particular crop.

For example if established for a particular wheat variety grown underirrigation and with a seed germination rate of 95% that a plantpopulation of 400 plants per square meter consistently gave the highestyields then this plant population would be the desired outcome whensowing. In one arrangement of the invention substantially preciseplacement results in a grid spacing of 50 millimeters by 50 millimetersto give each plant an equal area and therefore opportunity to realiseits maximum yield potential on a great proportion on the micro level andtherefore maximum yield on the macro level.

Less competition for root space, nutrients, moisture and light fromneighbours all contribute to an increase in yield made possible throughvigorous early growth of seedlings in the crop establishment phase. Thisresults in earlier ground cover with the shading by crop leaves slowingsoil moisture loss from sun and wind as well as smothering weeddevelopment. All these factors are known to seriously affect yields.

An apparent inventive or innovative step which is the maindifferentiating aspect of this apparatus and which sets it apart fromany prior art is the prior acceleration of the particles so that theyare travelling in the same direction and substantially at the samevelocity as the surface of the metering mechanism at the point wherethey arrive at the moving surface of the metering mechanism and therebyenabling to substantially increase the speed at which seeds can beaccurately planted compared to existing ground contact seeding machines.

As to date there has not been an apparatus which could sow seed at theground speeds obtainable with this invention. Other aspects which arepart of the overall apparatus and are original in their applicationinclude:

-   1. The use of electronic sensor device to establish particle exit    velocity from delivery tubes providing the ability to control the    exit velocity.-   2. The use of venturis with controlled adjustable outputs to vary    the exit velocity of particles.-   3. The use of electronic sensor device to count seeds as well as    tube blockage monitoring.-   4. The use of electronic sensor to control seed exit velocity so    that seeds can be shot into the less dense soil to a predetermined    depth.-   5. The use of a roller to prevent seed bounce.

All of the above are original applications which have to date not beenused nor required on slow moving seeding machines and as such are novelin their application.

It should be noted that accelerators based solely on mechanical,pneumatic or gravitational means, whilst being part of the generalconcept, are on their own generally difficult to use as their settingswould continuously have to be altered for changes of drum speed whichmoves relative to the ground speed of the machine.

A combination of gravity and mechanical would therefore seem to give thebest overall results and is very practical to implement.

BRIEF DESCRIPTION OF THE DRAWING

In order that the invention can be more readily understood embodimentsof the invention will be described by way of illustration only withreference to the drawings wherein:

FIG. 1 is a schematic block diagram showing conceptual interengagingfunctions on a seeding apparatus in accordance with embodiments of theinvention.

FIG. 2 is a schematic cross sectional view of a combinationgravitational and mechanical feeding means to drum metering means of aseeding apparatus in accordance with a first embodiment of theinvention;

FIG. 3 is a partial cross sectional view of a main particle storage binof one form of Sections 1 and 2 of seeding apparatus of FIG. 1 with areceival hopper fed by gravity;

FIG. 4 is a partial cross sectional view of a main particle storage binand adjacent receival hopper of a second form of Sections 1 and 2 ofseeding apparatus of FIG. 1 with the receival hopper supplied by a augeror the like from the main storage bin;

FIG. 5 is a partial cross sectional view of a gravity feed system havingvertical feed with particle velocity control flap providing adjustableaperture feeding to a drum metering means in accordance with a secondembodiment of the invention;

FIG. 6 is a partial cross sectional view of a second gravity feed systemhaving vertical feed redirected across the drum with particle velocitycontrol flap providing adjustable aperture feeding to a drum meteringmeans in accordance with a third embodiment of the invention;

FIG. 7 is a partial cross sectional view of a gravity feed system to adrum metering means with a speed control driven roller controllingparticle velocity feed to the drum in accordance with a fourthembodiment of the invention;

FIG. 8 is a partial cross sectional view of a gravity feed system to adrum metering means with a speed control driven belt feed systemcontrolling particle velocity feed to the drum in accordance with afifth embodiment of the invention;

FIG. 9 is a partial cross sectional view of a gravity feed system to adrum metering means with a speed control double belt drive feed systemcontrolling particle velocity feed to the drum in accordance with asixth embodiment of the invention;

FIG. 10 is a partial cross sectional view of a gravity feed system to adual drum metering means with a speed control double belt drive feedsystem controlling particle velocity feed to the dual drums inaccordance with a seventh embodiment of the invention;

FIG. 11 is a partial cross sectional view of a gravitational acceleratorfeed system in accordance with an eighth embodiment of the inventionwith the gravitational accelerator including a particle velocity controlflap providing adjustable aperture output feeding;

FIG. 12 is a partial cross sectional view of a gravitational acceleratorfeed system in accordance with a ninth embodiment of the invention withthe gravitational accelerator including a redirecting slide and aparticle velocity control driven roller;

FIG. 13 is a partial cross sectional view of another gravity feed systemin accordance with a tenth embodiment of the invention with thegravitational accelerator including a redirecting slide and a particlevelocity control flap providing adjustable aperture output feeding witha double belt seed velocity control section;

FIG. 14 is a partial front elevation of a seed metering drum of aseeding apparatus in accordance with the invention;

FIG. 15 is a partial cross sectional view of the seed metering drum ofFIG. 14;

FIG. 16 is a partial cross section of an external air jet form of aseparation device for releasing seed from the drum metering means;

FIG. 17 is a partial cross section of a rotating brush form of a furtherseparation device for releasing seed from the drum metering means;

FIG. 18 is a front elevation of a partial view of an adjustablemechanical deflector form of a separation device for releasing seed fromthe drum metering means;

FIG. 19 is a cross section of a seed metering drum with a continuousbelt sealing a majority of the drum except the metering segment of thedrum;

FIG. 20 is a cross section of a seed metering drum with a hollow sleeveused to block apertures which are not in the metering segment of thedrum thereby concentrating suction in the metering segment of the drum;

FIG. 21 is a cross section of a seed metering drum with a flexiblestationary belt sealing a majority of the drum except the meteringsegment of drum;

FIG. 22 is a cross section of an airjet release mechanism of the drummetering means and a delivery system having an ejection velocity controlsystem using an adjustable flow venturi in line with an outlet deliverytube;

FIG. 23 is a cross section of a means of incorporating metered particlesinto the soil including dual rollers and resilient tynes therebetween;and

FIG. 24 is a cross section of a means of incorporating metered particlesinto the soil including a single roller and preceding resilient tynes.

Throughout the drawings constant numbering is used to represent the samefeature in different embodiments. The full listing of featuresidentified by numbers is as follows:

-   -   1. Seed metering drum.    -   2. Drum support bearing and vacuum seal housing    -   3. Apertures in drum surface within a row    -   4. Rows showing offset apertures    -   5. Drum support frame    -   6. Vacuum or suction generating mechanism    -   7. Drum rotation mechanism    -   8. Apertures with metered particles attached    -   9. Vacuum cut off particle ejection roller    -   10. Air jet blockage cleaner and ejection mechanism    -   11. Particle trajectory separation area    -   12. Blockage in aperture    -   13. Blockage cleared    -   14. Particle trajectory separation guides    -   15. Trajectory of metered particles    -   16. Trajectory of unselected particles    -   17. Direction of drum rotation    -   18. Air jet particle ejection nozzle    -   19. Air jet    -   20. Rotating brush particle ejector    -   21. Direction of brush ejector rotation    -   22. Adjustable mechanical deflection particle ejectors    -   23. Deflected & ejected metered particles    -   24. Metering segment of drum    -   25. Vacuum restricting wedge    -   26. Belt idler roller    -   27. Continuous belt used to block apertures which are not In the        metering segment of the drum thereby concentrating suction In        the metering segment of the drum 24. The belt Is sucked onto the        drum surface and Is driven by the rotation of the drum.    -   28. Continuous belt tension roller    -   29. Sleeve used to block apertures which are not in the metering        segment of the drum thereby concentrating suction in the        metering segment of the drum 24. The sleeve can be hollowed        internally so only the perimeter of Its under side contacts the        drum thereby minimising drag.    -   30. Main storage bin for particles    -   31. Receival hopper for particle feed system    -   32. Agitator to assist flow of particles in feed system    -   33. Means for transferring particles from main bin to receival        hopper—may be mechanical such as auger, conveyor belt or        pneumatic system    -   34. To particle velocity control section    -   35. Shut off valve    -   36. Particles—seeds    -   37. Particles in gravitational flow    -   38. Particle velocity control flap—adjustable gap    -   39. Particle velocity control driven roller—adjustable        rotational direction, velocity and gap    -   40. From gravitational acceleration section    -   41. Particle velocity control continuous belt    -   42. Particle velocity control continuous belt idle roller    -   43. Particles which already have momentum    -   44. Particle slide guide    -   45. Particle flow rate control adjustable valve    -   46. From receival hopper    -   47. Gravitational acceleration chamber    -   48. Particles undergoing gravitational acceleration    -   49. Slide segment on a gravitational accelerator    -   50. Stationary belt used to block apertures which are not In the        metering segment of the drum thereby concentrating suction in        the metering segment of the drum 24.    -   51. Particle flow restrictor used to provide constant pressure        of particles on the control valve 45 as the height of particles        in the receival hopper changes    -   52. Area of constant pressure under restrictor 51 providing        constant flow to control valve 45    -   53. Ground roller—press wheel    -   54. Sprung tynes—ground ticklers—height and action adjustable    -   55. Air dissipation area in which excess air pressure from        delivery tube dissipates    -   56. Particle delivery tube    -   57. Particles shot under roller to prevent particle bounce    -   58. Soil which has been lifted by ticklers 54 and has air mixed        in making it less dense than soil below    -   59. Ground level    -   60. Particle to soil incorporator support frame—height        adjustable    -   61. Particles shot Into strata containing less dense soil    -   62. Venturi—flow rate adjustable    -   63. Pressure adjustable air nozzle into venturi enabling        velocity control of particles in delivery tube    -   64. Suction inlet section of venturi accepting meter particles    -   65. Venturi outlet transferring metered particles into delivery        tube    -   66. Electronic sensor—various functions some examples being        particle counting, particle velocity monitoring and delivery        tube blockage monitoring    -   67. Particle metering drum hollow support axle    -   68. Particle metering drum support bearing and vacuum seal    -   69. Particle metering drum drive gear or sprocket    -   70. Unselected or non metered particle recycle system—mechanical        or pneumatic means    -   71. Area of low pressure within particle metering drum    -   72. Spring tension on vacuum cut off roller 9    -   73. Particle velocity control belt drive roller    -   74. Evenly spaced metered particles    -   75. Area at which particle flow rate is controlled    -   76. Area at which particles arriving with momentum are arranged        prior to final velocity control    -   77. Area where particles which have been velocity controlled        arrive at metering drum moving surface

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

Referring to the drawings there is shown a method of seed distributionusing a mobile ground engaging seeding apparatus including a movingmetering system having a moving part of which the movement assistsmetering of seed to be distributed. FIG. 1 of the drawings shows theoverall system broken down into a number of sections in a diagrammaticform.

In FIG. 1 there is shown a seeding apparatus that includes a mainparticle storage bin as detailed by Section 1. Material passes to aparticle receival hopper, agitator, separator and sorter as categorisedin Section 2. The system is then broken down into 7 sections withSection A comprising the particle, flow rate and velocity control meanswith accelerator and braking components. Section B receives theparticles at controlled velocity and selection of the individualparticles together with trajectory separation occurs. The non selectedparticles enter the excess particle recycle system of Section F toreturn to the main particle storage bin of Section 1. However theselected particles on a trajectory from Section B proceed to theparticle conveying means of Section C including ejection velocitycontrol means. Section D monitors particle exit velocity and theparticles proceed to Section G where the particles are incorporated intothe soil. Section E is an electronic function monitoring control whichmonitors and controls various elements of Sections 1 and 2 as well asSections A, B, C, D, F and G.

The description will particularly describe one embodiment of an entiresystem and then provide examples of some variations of each section.

FIGS. 3 and 4 relate to options of Sections 1 & 2 of FIG. 1. FIG. 3shows a main storage bin with a receival hopper fed by gravity situatedbelow while FIG. 4 shows a receival hopper supplied from a separate mainstorage bin.

The system includes a feed system for providing seed from a seedreservoir to the moving metering system, the feed system providingsubstantial control of speed and amount of seed to be able toeffectively interact with the moving metering system. The seed to bedistributed is fed to a particle receival hopper, agitator, separator,sorter and accelerator. These will be further described in Section Awhich in various embodiments is shown in FIGS. 5 to 12.

The material is fed to an individual particle selection and trajectoryseparation. The moving metering system has a drum with a series of holeseach smaller than the seeds and an internal negative pressure such thatrotation of the series of holes and suction of the seeds to the drumprovides a metering of the seed. This will be further described inSection B and shown in various forms in FIGS. 13 to 20. The feed systemprovides seed at substantially stationary relative position between theseed from the feed system and the moving surface of the metering system.The feed system further has an acceleration means for feeding seed fromthe feed reservoir to the external surface of the drum means at a speedsubstantially equal to the speed of rotation of the surface of the drummeans.

As will be further described in Section C, a delivery means is providedfor delivering the metered distribution of seed and having a deliverymechanism which substantially controls the speed and direction of theseed such that the metered seed is delivered substantially as metered.The feed system provides seed to the moving metering system on acircumferential side of a rotationally moving metering system providingselection and metering of seed to the delivery system.

The metered material has its exit velocity monitored and controlled tobe seeded at required spacing. This will be further described in SectionD.

The incorporation of the seed into the soil will be further described inSection G and with reference to FIGS. 22 and 23.

The control is undertaken by electronic function monitoring control aswill be further described in Section E.

The excess that is not picked up is collected by the excess particlerecycle system and returned to the main particle storage bin. This willbe further described in Section F.

However FIG. 2 provides one example of an overall diagrammaticcross-sectional view of a seed distribution method and apparatus in apreferred embodiment showing sections A, B, C, D, and F. This embodimentof the invention shows one from the range of options available formetering and distributing seed. The apparatus provides metered seedplacement from a continuously moving vehicle in a predetermined,uniformly spaced array and allows for recycling of unselected seeds.

The seeding apparatus includes a frame integral with or attachable to avehicle. A seed distribution metering means for metering the seed to bedistributed is mounted on the frame and includes a seed metering drum Imounted on the frame with a circumferential cylindrical peripheral walland having a horizontal axis of rotation around a hollow support axle67. A drive gear 69 drives the rotation of the drum 1. The drum 1 has apredetermined arrangement of a plurality of spaced apertures 3 smallerthan the size of the seed to be metered. The drum 1 is connected to avacuum generator 6 providing area of low pressure 71 in an annular areabetween the hollow support axle 67and the circumferential cylindricalperipheral wall of the drum 1. The hollow drum 1 is supported by thehollow axle 67 which simultaneously provides the connecting channel bywhich low pressure vacuum is applied to the drum 1. A drum bearing andseal 68 separate the annular area of low pressure 71 from the hollowsupport axle 67 and allow drum rotation around the stationary axle. Ameans 25 and 50 on the outer side of the circumferential cylindricalperipheral wall partially seals the outer side of the drum 1. A drumrotation means is thereby provided for rotatably mounting said drummeans on said frame and for rotating the drum at a required speed. Thevacuum generator for generating a negative pressure is fluidly connectedwith said drum and operatively communicating with said apertures toprovide a vacuum suction through the apertures.

A receival hopper 31 is mounted on the frame above the drum 1 forreceiving and holding seed for distribution. The receival hopper is fedfrom a main storage bin alongside by a transferring means 33 extendingfrom a lower portion of the main storage bin 30 to an upper side of thereceival hopper. The transferring means can be a rotating auger or othermeans. An agitator 32 is located within the receival hopper 31 toprovide a rotating, vibrating action or both to prevent blockages andensure smooth flow of seeds. A particle flow restrictor 51 is providedin a lower section of the funnelling receiving hopper 31 in order toprovide a broad control of feeding of seed. The particle flow restrictor51 provides an area 52 of constant pressure and feeds the seeds to anoutlet chamber of the feeding system for feeding seeds from the receivalhopper to the external surface of the drum 1. An adjustable flow ratecontrol valve 45 at the top of the acceleration chamber 47 meters seedto give an amount of seeds and at the correct density required for aparticular drum surface rotational speed.

This outlet chamber forms a gravitational acceleration chamber 47 whichis the acceleration means corresponding to Section A for feeding seed ata required speed relative to the speed of the drum 1 and the speed ofthe seeding vehicle. The acceleration segment 47 of the acceleratormeans comprises a first gravitational drop portion which is ofsufficient predetermined height to provide the required acceleration ofparticles from stationary to a higher velocity. The acceleration segment47 also includes an angled slide segment 49 for redirecting the seed toa path across a portion of the circumferential cylindrical peripheralwall of the drum 1. At the end of the slide there is an adjustableparticle velocity control flap 38. The interaction between the flow ratecontrol valve 45 and the particle velocity control flap 38 enables seedswhich have gained momentum to be presented at the moving drum surface atthe density and speed required. Section A also includes a velocitycontrol means which in this form includes two particle velocity controlcontinuous belts 41 that are spaced on either side of the flow pathadjacent the expected engagement of the seeds with the drum 1. Thespacing and the rotation of the continuous belts 41 by the drive rollers73 can be altered to alter the speed of the seed and spacing of the seedto ensure maximum effectiveness of the seed metering drum 1. The driverollers 73 can be independently driven or driven mechanically off thedrum 1.

The rotating drum I with a series of holes located on thecircumferential cylindrical peripheral wall and which are each smallerthan the seeds and an internal negative pressure in the internal annulararea 71 of the drum causes rotation of the series of holes and suctionof individual seeds to individual holes of the drum 1 to provide ametering of the seed

The increased effectiveness of the internal low pressure 71 is providedby a means on the outer side of the circumferential cylindricalperipheral wall which partially seals the outer side of the drum 1. Thisis provided by a stationary flat belt 50 fitting around the outersurface of the drum 1 away from the metering portion to minimise vacuumsuction required. The flat belt 50 is retained adjacent the drum by thesuction pressure applied through the perforations and is of material tominimise drag caused by the drum's rotation. This belt is used to blockthe drum perforations on a large part of the circumference therebyreducing the size and volume of the vacuum generating mechanismrequired.

Wedges 25 are used to block unused perforations on the drum, which hasthe same function as flat belt 50. The use of belt and wedges assist inconcentrating and maximising the suction effect produced by the partialvacuum inside the drum onto the seed separation section and also resultsin not having to use as large a fan or vacuum pump for a given drumsize.

A release mechanism 18 is incorporated for countering the hold of thevacuum suction on the seeds, whereby as the drum 1 rotates the seedsfrom the hopper means are held against the apertures by the reducedinternal pressure of the drum 1 and are carried on the peripheral wallof said drum means from said hopper means to the release mechanismwhereat the seeds are released into delivery system of Section C to theseedbed. The release mechanism is located along a circumferentialportion around from the metered section such that the detachment ofseeds from the circumferential cylindrical peripheral wall of the drumforms a metered seed trajectory 15. In the embodiment shown there is apositive pressure air jet nozzle 18 at this circumferentially spacedposition from the metered position with the nozzle 18 directing an airjet 19 to eject metered seeds 74 off the drum outer surface along thetrajectory of metered particles 15.

There is also a recycle means 70 for unmetered seeds following atrajectory 16 separate to the metered/separated seeds trajectory 15 asthey were not held by the lower pressure 71 to the holes on the drumouter surface and redirected on the circumferentially offset trajectorybut instead continued in the substantially straight trajectory providedby the acceleration means and velocity control means. The recycled seedsare returned back to the main storage bin 30.

In one form the selected metered particles 74 following the trajectory15 enter suction inlet section 64 of venturi 62 and by pressureadjustable air nozzle 63 leading into venturi 62 provide at the venturioutlet 65 seeds at the required velocity to proceed along particledelivery tubes 56 past electronic sensors to the seedbed so that thereare evenly spaced seeds 74 leaving the seeding apparatus. Control of theseeding can be adjusted by the electronic function monitoring control ofSection E to give relative stationary placement of seeds. Flexibletubes, one per row, allow for row spacings to be adjustable.

However to further understand the seed distribution method and apparatusit is necessary to separately look at various sections in detail andshow some of the proposed variations.

Sections 1 and 2: Particle Storage and Feeder

As shown in FIGS. 2, 3 and 4 a receival hopper 31 is located above thedrum means 1 and receives the seeds from a main storage bin 30. This isachieved by gravity when as in FIG. 3 the receival hopper 31 is placedbelow the main storage bin 30. However as shown in FIGS. 2 and 4 theseed can be transferred by pneumatic or mechanical means if the receivalhopper 31 is located next to the main storage bin 30. This allows forthe height of the seeding apparatus to be limited. It also allows forthe receival hopper to be adjustable in height to allow for differentdistances and greater gravitational acceleration of seed between leavingthe receival hopper 31 and encountering the drum 1. In some cases whenthe particles are of a type which do not flow freely under gravity, theassistance of one or more agitating mechanisms 32 may be required toinduce flow and prevent clogging. The agitation can be a vibratingapparatus or as shown a rotating mechanism or combination of these. Theagitator provides an even uninterrupted supply of seeds to the feedingsystem.

Section A Particle Flow Rate and Velocity Control

FIG. 5-13 relate to Section A of the block diagram of FIG. 1. Section Aprimarily concerns a number of functions in preparing the particlesprior to their presentation at the drum surface of Section B.

An accelerator is required to accelerate the stationary particles fromthe feed hopper 31. The accelerator can be mechanical, pneumatic or anyother means to give the desired outcome of accelerating the particles toa speed substantially the same and in the same direction as therotational speed of the drum surface. The particles may travel slightlyslower or slightly faster than the drum surface. If the speeddifferential is too large the drum will fail to pick up seeds. If theparticle speed is too slow the drum will fail to pick up seeds—thisbeing the limitation of the prior art. Seeds already selected will beknocked off by those travelling past at a rate which is too fast.

FIG. 5 shows a gravity induced free fall system 40 which can be suitablefor some types of particles to accelerate seeds vertically past acircumferential surface of a rotating drum 1. FIG. 6 shows a variationof a gravity feed system which exposes seeds to an increased section ofthe drum surface to enhance the likelihood of connection of seeds to theholes of the circumferential surface of the drum by the internal lowerpressure 71. The greater possible drum contact surface also allows forfaster rotation of the drum.

FIG. 7 shows the addition of an adjustable direction and variable speeddriven roller 39 to assist flow and control seed velocity on a gravityfeed system. The adjustable accelerator roller 39 can accelerate ordecelerate the particles as required. Further this arrangement alsoallows gap adjustment between the roller 39 and the drum 1 and speedvariation to produce the required outcome. The driven roller 39 can berotated clockwise or anticlockwise. When the gap between drum 1 androller 39 becomes small the roller may tend to compress and damage seedsif travelling in the anticlockwise direction. In extreme cases blockagesand jamming may result. By reversing the directional rotation of theroller 39 to clockwise it will tend to prevent blockages as well ascontrolling the speed of the seeds between it and the drum surface.Having this bi-directional facility in creases the range of optionsavailable.

FIG. 8 shows an adjustable variable speed single continuous belt 41 toassist flow and control seed velocity on a gravity feed system. A singlevertical moving continuous belt 41 extending around drive roller 73 andidler roller 42 is located on one side of a gap formed by the drumsurface on one side and the belt on the other. The size of the gapbetween belt 41 and the metering surface of the drum 1 assists in theacceleration or deceleration of the particles as they pass. The belt 41need not only be an accelerator but can be a braking system if requiredwhen the flow speed induced by gravitational free fall of the particlesis greater than required. The belt simply by travelling at a slowerspeed will have frictional effect on the flow forming a braking effectto provide the correct particle speed.

FIG. 9 like FIG. 10 show adjustable variable speed double continuousbelts 41 to assist flow and control seed velocity on a vertical gravityfeed system. The seeds are moved between two moving belts so that theseeds are frictionally engaged by the belts and thereby accelerated ordecelerated. The gap between the belts and the belt speed areadjustable. The belts can be flat, contoured or shaped or coated in away to provide the desired outcome.

FIG. 10 shows one arrangement of a multi drum system with seeds arrivingfrom between adjustable variable speed double continuous belts 41 toassist flow and control seed velocity on a gravity feed system. This isan example of a multiple drum system which can be used to increase thesowing width of a seeding apparatus or where small spacings betweenseeds are required at higher sowing speeds. Another option would be toplace drums above one another or multiples of both arrangements.

FIG. 11 shows a gravitational accelerator used to give the seeds initialmomentum and to control flow rates while FIG. 12 shows the addition of aredirecting slide as part of the gravitational accelerator. The figuresshow slight conceptual variations in that the acceleration device inFIG. 12 can be moved up and around the drum to a different location toallow non vertical contact of the seed with the drum. This allows forthe spray pattern of the excess non selected particles to be guided awayrather than straight down as well as increasing the area on the drumsurface where seeds are selected as shown in FIG. 2.

At the end of the gravitational accelerator of FIG. 11 there is anadjustable particle velocity control flap 38 which allows the seed tomaintain momentum while acting as a braking means to control both thedensity and speed of the seeds to be presented to the drum surface. Theinteraction of the flow rate control valve 45 and the flap 38 enablesthe precise control of the seed density and speed. The same function isperformed in FIG. 12 by an adjustable particle velocity control drivenroller 39.

The function of the accelerator is to accelerate the seed so that whenpresented at the drum surface as will be described in Section B theseeds will be travelling in the same direction and preferably at thesame speed as the drum surface where both make contact. Ideally theseeds should travel at slightly slower than the drum surface thuscompensating for misalignment of aperture and seed. If the seeds aretravelling too much faster than the drum apertures they will knockattached seeds off as they travel past. In FIGS. 5 to 10 it can be seenthat the moving drum surface in itself provides acceleration assistanceby both the action of the moving suction pressure on the particles andalso by being a moving floor.

The hopper, agitator and accelerator ideally have the dimensions so thatseeds will be presented to the drum surface evenly but adjustably andacross the required drum width. Typically the width of the feedingsystem shall be similar to that of the drum means.

FIG. 13 shows an acceleration system having a gravitational accelerationsection 47 and a redirecting slide 49 feeding seeds into a double beltseed velocity control section. The angle of redirection is the tangentto the drum at the metering drum moving surface 77 beginning at aroundabout 2 o'clock on the drum 1. This is different to the other examplesin FIGS. 5 and 7 which are vertical feed to drum metering surface 77 at3 o'clock. The angle of the redirecting slide 49 allows choice oflocation of drum metering surface 77.

The gravity acceleration system has a mechanical velocity control systembetween 47 and 77 attached to vary the velocity and density of theparticles so they arrive at the drum surface as required. Like FIG. 11there is an adjustable particle velocity control flap 38 which allowsthe seed to maintain momentum while acting as a braking means to controlboth the density and speed of the seeds to be presented to the drumsurface.

At the base of the particle receival hopper 31 is a particle flowrestrictor 51 which provides a constant height 52 of particles above thecontrol valve 45 thereby providing a constant feed pressure irrespectiveof the particle height in the receival hopper 31. A slide 44 helps guidethe particle into the area 75 where the particle flow rate is metered.By accurately controlling the opening at 75 with the control valve 45which maybe driven by a stepper motor as one example, the desired amountof particles arriving at the drum surface 77 is achieved. Ideally thedensity of the flow of particles arriving at the moving drum surfaceshould be such that no pick up failures occur. If the density isinsufficient inter-particle gaps are too large and particle pick-upfailures can result. If the density is too large then an excessiveamount of unselected particles will have to be recycled from Section F.

The particles accelerate in the gravity acceleration section 47 so theyarrive at the mechanical particle velocity control belts at 76.

Setting the height of 47 to that required for the maximum velocityrequired at the drum surface 77 enables the control of the particlevelocity by the belts 41 to be more efficient. As an example setting theheight 47 at around 1 meter will result in the particles accelerating toa velocity of about 4.5 m/sec when they arrive at the belts 76.Adjusting the particle velocity control flap 38 gap ensures that theparticles orientate themselves to provide the required density and speedon arrival at the metering drum surface 77.

Adjusting the velocity of and the gap between the belts 41 which aredriven by rollers 73 and can be accurately controlled gives the abilityto provide acceleration, maintenance of velocity or braking action onthe particles.

Calculating the weight and density of particles required for aparticular metering drum surface velocity gives the flow rate per secondof particles required to arrive at the drum moving surface. This flowrate is controlled at 75 by 45.

The slide 49 is provided so that the particles arrive at the mechanicalbelts section at the same angle as that of the belts that being thetangent to the drum at 77.

As functions including particle flow rate controlled by valve 45, speedof mechanical belts 41, metering drum surface velocity, are allmonitored and controlled by section E it is straight forward that therelationship between all these functions can be adjusted to provide therequired results.

Section B: Particle Selection, Separation and Trajectory Separation

FIGS. 14-21 relate to Section B of the block diagram of FIG. 1. FIG. 14shows a seed metering drum with rows 4 of offset apertures on itssurface. FIG. 15 shows a partial cross section of a drum with meteredseeds being separated from unselected seeds with one example of aseparation device together with one example of a blockage cleaner.

Seeds that have been accelerated are presented from the accelerator beltto a rotating drum's outer perimeter at 77 as shown in FIG. 13. The drumperimeter has rows of evenly spaced holes 3 through the surface withhole spacing which may be offset between rows.

The drum contains within it a partial vacuum that is created by anexternal vacuum generating mechanism connected through axial tube to thedrum means. This creates an area of considerably lower pressure withinthe drum than the external atmospheric pressure. The pressure differencecauses the seeds to be held onto the holes on the perimeter of the outersurface of the drum. The holes therefore must be smaller than the seedsto prevent the seeds travelling into the drum itself. By substantiallyblocking the holes the seeds help to maintain a negative pressure insidethe drum as material or air is predominantly prevented from entering thedrum to break the partial vacuum or decrease the pressure differentialbetween internal and external pressure. By selecting the correct holediameter for a particular seed type predominantly only one seed willadhere to each hole and particles will not jam inside a hole.

The drum rotation means can be mechanically driven by a ground engagingwheel or driven by a motor which may be speed controlled. Speed controlallows for variation of drum speed relative to the ground speed of theseeder thereby enabling minute variations to be made to the spacing ofparticles within a row regardless of speed of seeder. This variation isalso possible while in operation therefore not requiring stopping andreadjusting. Such variations also allows for variation of the optimumseeding density according to localised variations that have beenidentified from previous harvests. This could be due to sections ofbetter soil types within an area, different moisture availability,leeward side of hill or North facing hill for Southern Hemisphereproperties or any other reason.

FIG. 15 shows a vertical cross section of the drum. A vacuum cutoffroller 9 inside the drum 1 releases the selected particle at a set point11 by cutting off the pressure holding the particle onto the drum outersurface.

Also other examples of many available options FIGS. 16, 17 and 18 showadditional external methods which may be used to release the selected(metered) particles off the drum surface.

FIG. 15 shows the use of an internal airjet 10 using positive airpressure to clear a blockage 12 and 13. It is used as a backup ejectiondevice when used with 9 or as an ejection device on its own without thepresence of 9. The unselected particles fall away under gravity to forma first trajectory being the unselected particle trajectory 16 whilstthe selected (metered) particles at 8 are rotated to another point onthe drum 11 to be released by 9 to form a second different trajectorybeing the metered particle trajectory 15 thereby providing accurateseparation and metering.

FIG. 16 shows an external airjet 19 from nozzle 18 as a releasemechanism.

FIG. 17 shows a further option of a rotating brush used to perform thisfunction. A simple deflection device on the outer surface of the drum istherefore all that is required. FIG. 18 shows the use of adjustabledeflectors 22 as another example of a separation device.

The drum in one useful embodiment has a circumference of 1 meter withabout 100 holes 10 millimeters apart on each row of the drum perimeter.With a ratio between ground speed and drum surface speed set at 5 to 1,and the drum rotating at about 167 revolutions per minute, a seed isplanted every 5 centimeters within a row when the vehicle is travellingat a ground speed of 50 kilometers per hour.

The diameter of the drum can be varied to give the required outcome.

The seeds, which are held onto the outer surface, are separated from theair stream of unattached seeds by the rotational movement of the drum.The unattached seeds continue in the direction initialised by theaccelerator in the feeding system while the attached seeds which havebeen separated from the main stream have travelled around to a positionwhere they are released off the drum's surface. The release of theseseeds can be done in a variety of ways including deflection mechanismson the outer side or by temporarily cutting off the vacuum supply on theinner side of the drum. On separation these seeds will continue totravel off along the tangent at the point of release, which will be atrajectory 15 different to the trajectory 16 of main stream of seeds,which are not attached.

In this way the feeding system and drum system of Section B has provideda mechanism for selecting seeds at regular intervals and separatingthose selected seeds from the main seed stream thereby accuratelymetering those separated seeds allowing for the counting and accuratespacing of those seeds. The selected separated seeds continue on to theexit system of Section C while the unseparated seeds in the main streamcontinue onto the recycling system of Section F.

As the seed stream, which has been accelerated by the feeding system ofSection A, can be several seed widths thick it presents two surfaces.FIG. 10 shows one side of this seed stream making contact with one drumsurface in Section B. An additional drum placed directly opposite thefirst and rotating so that it selects seeds from the other side of thestream can be utilised. This means the accelerated seed stream passesbetween both drums. Furthermore as the unattached seeds in the streamtravel onto the recycle system of Section F additional drums can beadded below in a vertical tiered format.

The use of multiple drum set-ups can substantially increase a machine'sground speed capability and also the area covered in one pass. Also fora given ratio, drum surface speed relative to the ground speed of themachine, the surface speed of the drum will always be constant withvarying drum diameters. There presents an option to use the mostpractical drum diameter for the purpose. As the diameter of the drumdecreases the revolutions will increase while the drum surface speedremains constant. A smaller diameter drum will have less holes aroundits circumference, which in turn will require a smaller suction pump butthe centripetal forces on the seeds attached to the drum outer surfacewill be greater. The optimum is therefore a balance between the two.

FIGS. 19, 20 and 21 show the use of various means 27, 29 and 50 to blockthe apertures on the drum away from the metering area of the drum 24 tohelp to concentrate the suction pressure for effective seed pick up atthe metering section of the drum 24.

Referring to FIG. 19 there is shown a seed distribution apparatus with acontinuous belt 27 travelling around a set of rollers 26. The belt issucked onto the surface of the drum by the negative pressure inside thedrum through the holes on the surface of the drum. The rotation of thedrum causes the belt to be driven. A tension roller 28 ensures beltadhesion to the drum surface and belt rotation by the drum. The purposeof this belt is to block holes on the section of the drum surface notrequired for particle separation thereby concentrating maximum suctionin the section where particle separation occurs. This feature enablessmaller volume suction pumps to be used for a given drum size. Wedgeshaped restriction devices 25 are used in the gaps.

Another example providing the same feature is shown in FIG. 20 using anair restricting sleeve instead of a belt. FIG. 20 shows a sleeve with ahollowed interior as another example of a device to concentrate thesuction pressure on the seed pick up section of the drum. The sleeve maybe any shape with one example being a hollow cavity with only theunderside perimeter making contact with the rotating drum therebyminimising drag.

FIG. 21 shows a thin flexible stationary belt—held in place by suctionthrough the drum apertures—as another example of a device to concentratethe suction pressure on the seed pick up section of the drum.

Any section of the drum covered by a belt or sleeve as well as thesection which has the seeds attached will assist in maximising thesuction concentration on the remaining open section for picking upfurther seeds.

Section C: Conveying Metered Particles and Controlling Particle ExitVelocity

FIG. 22 relate to Section C of the block diagram of FIG. 1. A flow rateadjustable venturi 62 as shown in FIG. 22 is one example by which themetered particles can be moved along an individual tube 56 to seed anindividual row. By varying the air flow through the venturi withadjustable pressure air nozzle 63 the speed of the seeds inside thedelivery tubes can be controlled. The tubes conveying the particles foreach row can be of varying lengths and set at variable spacings toprovide an substantial number of row spacings thereby covering a widedistribution area relative to the drum width. In the case where theparticles do not need to travel a great distance a venturi system maynot be required as the particles can fall down each tube under gravityto the soil.

Electronic sensors 66 at the end of each pipe which convey the meteredparticles and set the row widths enable particle flow or pipe blockagemonitoring. Sensors which monitor the exit speed of particles can alsobe used. By monitoring the exit speed of metered particles the abilityto maintain particles travelling at the same speed as the ground speedbut in the opposite direction allows for increased accuracy of particleplacement when the machine is travelling at speed and thereby minimisingparticle bounce. To set the travel speed of the particles within eachpipe for each row it is simply a matter of increasing or decreasing theairflow through the venturi delivery system as required. The sensorsystem also can provide for an accurate particle count.

Where particle speed monitoring is not required a sufficient air flowspeed can be set to move particles along delivery pipes withoutblockages occurring and maintain inter particle spacing. If particleshave to be slowed down (eg for deeper burial) they can be passed througha braking system to minimise particle bounce. One example is using acyclone. Particles which require deeper burial would usually be sown atslower speeds.

FIG. 22 shows metered seeds 74 from one row of drum along trajectory 15entering the suction side of a venturi 64 which has a variable pressurenozzle 63 allowing the velocity controlled transport of metered seedsalong the delivery tube 56. Also shown is an electronic device 66 at theend of the delivery tube which can perform various functions such ascounting, velocity monitoring and blockage detection.

The function of Section C is to accept the metered seeds from meteringdrum of Section B and convey them to the exit system. This process canbe accomplished in several ways including pneumatic or mechanical means.One method is to have a system involving the guidance of the meteredseeds originating from the rows of holes on the drum in Section B intothe suction sides of multiple venturis with one venturi corresponding toone drum row of apertures. The venturi system will cause the seeds totravel along tubes or veins to their required exit points. If flexibletubes are used this will allow the distance between exit points to bevariable allowing for the easy spacing of seeding row widths on theground. Each row results from a particular tube which originates from acorresponding venturi which gets seeds from a particular row of holes onthe drum in Section B and the spacing of each seed is set by thedistance between the holes making up the rows on the drum and therotational speed of the drum surface in relation to the forward groundspeed of the machine.

By controlling the venturi system one is able to control the exitvelocity of the seeds at the end of the tube. The advantage ofcontrolling and by implication being able to vary the exit velocity ofthe seeds becomes clear at high machine travel speeds. A machinetravelling in one direction at a ground speed of 50 kilometers per hourejecting metered seeds horizontally from a height of 0.5 meters and inthe opposite direction at 50 kph will substantially have the same effectas dropping seeds from stationary position at 0.5 meters heightresulting in minimal seed bounce and the maintenance of relatively evenseed spacing.

Section D: Particle Exit Velocity and Tube Blockage Monitor

The function of Section D is to monitor the velocity of seeds exitingthe tubes originating from Section C. This is achieved by electronicsensors 66 providing data which is transferred to the electronic controlof Section E where it can be used to alert the system to a blockageresulting in failure to seed on a particular row as well as enabling thesetting of exit velocities to match machine ground speeds.

The electronic sensors 66 can be used to count seeds thereby providing ameans for varying the seeding rates.

Section E: Control Unit

The function of Section E is to monitor and control the variousoperations on the machine including items such as seed exit velocity,machine ground speed, drum surface speed, drum revolutions per minute,seed count, area covered, seed rate per hectare, hopper seed levels,venturi output etc. Electronic control unit is a preferred embodiment;however some functions could be mechanical.

In the form where the drum of Section B is not driven mechanically by aground wheel but driven by a speed controlled electric motor, theelectronics in Section E would monitor signals from a ground wheelsensor and regulate the rate of drum revolutions as required. A distinctadvantage of this system over the mechanical ground wheel option is theallowability of small increments of about 1% increase or decrease of theseeding rate while in action. Therefore such a system can be connectedto a Global Positioning System (GPS) with paddock mapping informationand other tools to vary the rate as the optimal rate has been determinedto vary in any localised position. The electronic control also wouldenable the speed of the accelerator belt/roller system of Section A tobe varied relative to the drum surface while in action to accommodatevarious particle types. For example some seeds such as round soya beanswill flow more readily than odd shaped corn seeds.

Section F: Main Stream Unmetered Particles Recycle/Return System

The function of Section F is to collect all the seeds coming fromSection B which were not separated off by Section B and return them tothe main storage bin or to the receival hopper in Sections 1 and 2.

The excess particle recycle system of Section F can be varied. Forexample if Sections 2, A and B of the assembly are situated above themain seed storage bin the seeds will be lifted into the receival hopperof Section 2 from the main storage bin. In this form, means are requiredto lift the particles from the main particle storage bin into theparticle receiver hopper of Section 2. This can be pneumatic ormechanical methods such as conveyor, or auger. The excess particles willthen fall back into the main storage bin under gravity.

Another variation has the combination of Sections 2 as shown in FIG. 3as well as Sections A and B of the assembly situated below the main seedstorage bin. In this form the receival hopper can be supplied bygravitational means and the seeds from Section F can be returned to themain storage bin by pneumatic or mechanical means. FIG. 4 shows anothervariation with Section 2 at the side of the main storage bin.

Section G: Particle Incorporation into Soil

FIGS. 23 & 24 relate to Section G of block diagram of FIG. 1.

Conventional seeders used to sow cereal crops usually place seeds intothe ground along furrows which are formed by tynes or discs and thencovered by press wheels or other covering mechanisms. The depth of seedplacement is usually governed by soil moisture and plant type as somerequire greater seed placement depth. The speed of these planters isalso governed in part by sowing depth and is typically 5 to 15kilometers per hour.

Unlike the ability of some seeds with wing structures to fly on thewind, or some to attach themselves to passers by, nature has not to dateprovided seeds with a self burial mechanism. It can therefore belogically assumed that the deep placement of most seeds below thesurface is not normally required unless soil moisture is an issue. It iswell established that most grasses and therefore cereal crops willgerminate adequately if sown at just below the surface in conditions ofample soil moisture. In fact research has demonstrated that manyadvantages are gained by optimum depth of seed placement with theoptimum tending to be shallower rather than deeper.

Two examples of methods for incorporation of the metered seeds into thesoil at higher than conventional sowing speeds are shown in FIGS. 23 and24. These form part of the embodiment of the apparatus.

FIG. 23 shows two rollers 53 separated front and back but joined by acommon frame 60. This arrangement can be formed by single rollers ormade up of a combination of rollers or press wheels. Between the frontand back rollers are mounted ground ticklers 54 attached in a way thatthey can be moved vertically relative to the rollers 53. In this way thedepth of the ground ticklers can be set and maintained by the rollers asthey travel along the soil surface. The front roller can be contoured inany way which assists the placement of seeds eg it can be shaped toleave ridges and furrows in the soil. Allowing the front roller to belifted off the ground will also enable easier turning of the seedingapparatus.

As can be seen by the apparatus shown in FIG. 23 the tube 56 conveyingseeds is placed in front of the first roller in a position so thatexcess air which carries the seed in the tube can be dissipated 55before it reaches the roller thereby preventing the seeds from beingblown out from under the roller. The momentum of the seeds will enablean accurate placement 57 of each row of seeds under the front rollerthereby minimising seed bounce and maintaining accurate seed placement.

The ground ticklers 54 which can be of one of many shapes such as springtynes, are attached to the support frame and the depth andangle—variable aggression action—is set to provide the necessary soilmovement required to mix in and thereby incorporate the seeds. Theticklers are spaced on the support frame to maximise the requiredoutcome while minimising a raking of trash. The back roller which canalso be shaped to provide the required outcome presses the soil and seedtogether and expels excess air from the soil surface thereby assistinggermination. By setting the tips of the ground ticklers to for example20 millimeters, it would be difficult to bury the seeds any deeper than20 millimeters.

FIG. 24 shows a variation of the two roller unit above the seeds beingshot 61 into the soil 58 which has been fluffed up by the groundticklers 54 and the depth of seed placement being determined by thetickler setting as well as the exit momentum of the seeds. However toomuch momentum at an incorrect angle would create seed bounce, which isundesirable.

It should be understood that the above description is not limiting ofthe invention. Clearly other variations, which are understood by aperson skilled in the art without any inventive element, are includedwithin the scope of this invention as defined within the scope of thefollowing claims.

1. Seeding apparatus for metering and delivering seeds for planting in aseed bed, comprising: a rotatable seed metering element having a row ofcircumferentially spaced apart apertures on a rotating surface of themetering element; vacuum generating means arranged to draw air inwardlythrough said apertures whereby to attract and hold seeds to saidapertures; and means for rotating said metering element, a feed systemfor transporting seed from a seed reservoir to said metering element andplacing said seed at said rotating surface so that seeds are attractedto and held at said apertures; release means at a release point on themetering element for releasing seeds held at each said aperture of saidrotating surface and carried to said release point; and delivery meansfor delivering said seeds to a seedbed, wherein (a) the metering elementcomprises a drum, the said rotating surface being an externalcylindrical surface of the drum; and (b) in the feed system seeds areaccelerated to an increased speed and thereafter placed adjacent to thesurface of the drum and the metering apertures at a controlled speed. 2.Seeding apparatus according to claim 1 wherein the feed system comprisesflow rate control means whereby seed is fed at a controlled flow ratefrom said reservoir to the drum.
 3. Seeding apparatus according to claim1 wherein the flow rate control means comprises a variable restrictionto flow of seed into the feed system.
 4. Seeding apparatus according toclaim 1 wherein the velocity of seeds placed adjacent to the row ofapertures is controlled to be approximately the same as the speed of theapertures.
 5. Seeding apparatus according to claim 1 wherein the feedsystem comprises: acceleration means whereby seed entering the feedmeans is accelerated to a speed approximately the speed of thecylindrical surface of the drum; and velocity control means whereby seedleaving the acceleration means is placed adjacent to the row ofapertures and its speed is controlled.
 6. Seeding apparatus according toclaim 5 wherein the acceleration means comprises a chamber in which seedfalls downward whereby to be accelerated to an increased speed by theaction of gravity on the seed.
 7. Seeding apparatus according to claim 6further comprising supporting means for maintaining the drum and theacceleration means substantially level in use.
 8. Seeding apparatusaccording to claim 6 wherein the acceleration means further comprisesmeans for redirecting seed reaching a lower part of the chamber into adirection approximately tangential to the drum surface.
 9. Seedingapparatus according to claim 5 wherein the velocity control meanscomprises at least one moving belt that engages seed leaving theacceleration means the belt being of controllable speed.
 10. Seedingapparatus according to claim 9 wherein seed passes between the or a saidbelt and the surface of the drum over a portion of the circumference ofthe drum.
 11. Seeding apparatus according to claim 5 wherein thevelocity control means comprises an adjustable flap and wherein seedpasses between the flap and the surface of the drum over a portion ofthe circumference of the drum.
 12. Seeding apparatus according to claim5 wherein the velocity control means comprises a rotating roller whosespeed and direction of rotation are controllable and wherein seedleaving the acceleration means passes between the roller and the surfaceof the drum.
 13. Seeding apparatus according to claim 5 wherein thevelocity control means comprises one or more of a: a moving belt; arotating roller; and an adjustable flap engaging seed that leaves theacceleration means whereby to control the speed of the said seed leavingthe acceleration means.
 14. Seeding apparatus according to claim 5wherein the feed system includes an airjet for blowing seed along a paththat passes close to the surface of the drum and accelerates the seed toa speed substantially equal to the speed of the surface of the drum. 15.Seeding apparatus according to claim 5 further comprising recyclingmeans for capturing the unmetered seed stream and returning theunmetered seed to the seed reservoir.
 16. Seeding apparatus according toclaim 1 wherein: (a) the feed system places seeds adjacent to the drumsurface and apertures over a portion of its circumference; (b) therelease point is circumferentially past the said portion so that seedsheld at the apertures are carried beyond the said portion to the releasepoint and at the release point released in a metered seed stream, and(c) the said portion and the said release point are so positioned thatseeds not held at the apertures leave the drum surface in an unmeteredseed stream separate from the metered seed stream before reaching thesaid release point.
 17. Seeding apparatus according to claim 1 whereinthe release means comprises an air jet nozzle directing an air jet toeject metered seeds off the drum.
 18. Seeding apparatus according toclaim 1 further comprising means for controlling the speed of seedsreleased from the drum by the release means.
 19. Seeding apparatusaccording to claim 1 wherein seeds ejected from the delivery means aredirected under a roller rolling on the seedbed whereby to limit seedbounce on the seed bed.
 20. Seeding apparatus according to claim 1having electronic sensing means at a point of exit of metered seeds fromthe delivery system, the sensing means providing output adapted for atleast one of: (a) establishing exit speed of seeds from the deliverysystem for the purpose of controlling the seed exit speed and/or thedepth of planting of seeds in the seedbed; (b) counting seeds delivered;(c) monitoring for blockage of the delivery system.
 21. Seedingapparatus according to claim 1 wherein the row of apertures is one of aplurality of rows of apertures on the drum and wherein the deliverymeans is adapted to deliver a metered seed stream from each row ofapertures to one of a plurality of transversely spaced-apart rows. 22.Seeding apparatus according to claim 21 wherein said control meansfurther controls speed of exit of metered seeds from the deliverysystem.
 23. Seeding apparatus according to claim 1 further comprisingcontrol means adapted to control at least drum rotation speed, flow rateof seed in the feed system, and seed velocity at the drum surfacewhereby to provide a selected seed delivery rate related to ground speedand required seed spacing.
 24. A method for metering and deliveringseeds for planting in a seedbed including the steps of: providing arotatable seed metering element having a row of circumferentially spacedapart apertures on a rotating surface of the metering element; providingvacuum generating means arranged to draw air inwardly through saidapertures whereby to attract and hold seeds to said apertures; rotatingsaid metering element, by means of a feed system delivering seed from aseed reservoir to said metering element and placing said seed at saidrotating surface so that seeds are attracted to and held at saidapertures; at a release point on the metering element releasing theseeds held at each said aperture and carried to said release pointwhereby to form a metered stream of seeds; and delivering said meteredstream of seeds to a seedbed, wherein: (a) the metering elementcomprises a drum, the said rotating surface being an externalcylindrical surface of the drum; and (b) the method includes the step ofaccelerating seed in the feed system to an increased speed andthereafter placing the seed adjacent to the surface of the drum and themetering apertures at a controlled speed.
 25. A method according toclaim 24 including the step of controlling the flow rate of seed that isdelivered to the feed system and thence to the drum.
 26. A methodaccording to claim 24 wherein the controlled speed at which seed isplaced adjacent to the drum surface and apertures is approximately thesame as the surface speed of the drum.
 27. A method according to claim24 wherein seeds entering the feed system are accelerated by fallingthrough a vertical distance so as to be acted on by gravity.
 28. Amethod according to claim 24 wherein seed placed adjacent to the drumsurface is maintained adjacent to the drum surface over a portion of thedrum surface circumference.
 29. A method according to claim 28 wherein:(a) the release point is circumferentially past the said portion so thatseeds held at the apertures are carried beyond the said portion to therelease point and at the release point released in a metered seedstream, and (b) the said portion and the said release point are sopositioned that seeds not held at the apertures leave the drum surfacein an unmetered seed stream separate from the metered seed stream beforereaching the said release point.
 30. A method according to claim 28including the step of capturing the unmetered seed stream and returningthe unmetered seed stream to the seed reservoir.
 31. A method accordingto claim 24 wherein delivery of the metered stream of seeds is by adelivery system and the speed of exit of seeds from the delivery systemis controlled.
 32. A method according to claim 24 wherein seeds aremetered at a rate sufficient for seed placement at a selectablealong-row seed spacing and at a ground speed substantially greater than20 kilometers per hour, preferably between 30 and 60 kilometers perhour.